The discovery
Ants do not have noses, but that does not stop them from smelling cancer. Because of the abundance of olfactory receptors on their antennae, the insects have an incredible sense of smell and can use it to detect tumors.
The ability of ants
Cancerous tumours release distinctive versions of chemicals called volatile organic compounds that often occur in body fluids such as sweat and urine and in breath vapour. According to a new study published in the journal Proceedings of the Royal Society B: Biological Sciences, ants can smell those compounds in urine.
The technique used
Baptiste Piqueret, an ethologist at the Sorbonne Paris North University and lead author of the study, already knew that ants could detect volatile organic compounds that spread from cancer cells. Piqueret and his team began by transplanting human breast cancer tumors into mice and letting them grow. A technique called xenotransplantation.
Ants learn
They then collected urine from both tumour-laden and healthy mice. By placing a drop of sugar water in front of the urine of cancerous animals, the researchers trained the ants to associate the smell of tumours with a reward. When the team removed the sugar water, the insects lingered around the pee of the cancerous mice for about 20 per cent longer than the healthy mice because they were looking for a ‘treat’. Three colonies were involved in trying to learn the association of the smell of tumours with a reward.
The conclusion
“Chemical analysis confirmed that the presence of the tumor changed the odor of the urine supporting the behavioral results. Ants reliably detect tumor signals in mouse urine and have the potential to act as efficient and even cheap cancer biorecorders.”